| 摘要 |
<p>PURPOSE:To realize the gain control of an input signal, by using a working amplifier circuit formed with transistors (TR) for respective fixed bias and input signal and a similar working amplifier circuit whose one side is for a control signal TR. CONSTITUTION:Working amplification is performed by the working amplifier circuit formed with the TRs Q4 and Q5 whose emitters are connected commonly and prepared for the input signal S1 and the fixed bias via a DC power source E2, respectively, and the signal S1 and outputs of a negative phase and an in-phase appear at the collectors of the TRs Q4 and Q5. The output of the negative phase is processed at the similar working amplifier circuit consisting of the TRs Q6 and Q7 for respective control voltage V1 and fixed bias, and the output of the in-phase is processed at the similar working amplifier circuit and the gain of the signal S1 changes corresponding to the voltage V1. The gain is changed similarly for the input signal S2 on the other side, and it is possible to control the individual gain control and addition quantity for plural input signals by a DC voltage.</p> |
